Analysis of a complex mixture such as blood can be difficult but provides valuable information. For example, CD4 T cell levels can reflect the course of disease in AIDS patients, cellular lymphoid and myeloid markers can aid leukemia and lymphoma diagnoses, and the presence of errant epithelial cells in the blood may signify a metastasizing cancer.
Such complex mixtures can be analyzed by fluorescent activated cell sorting (FACS), a technology that can quantitate marked analytes and also separate them out from the mixtures. Another popular method of cell separation involves magnetically labeling a target population of cells, e.g. with ferromagnetic beads, followed by sorting the labeled cells by passing them through a receptacle positioned within a magnetic field, a process also known as magnetic activated cell sorting (MACS). Despite their widespread use, FACS and MACS technologies have disadvantages, for example, they require machinery that is expensive and difficult to maintain. FACS technology has the added disadvantage of having limited portability.
Given the heavy demand, new approaches and technologies for cell sorting are needed for medical diagnostics and other applications.